1. Field of the Disclosure
The present disclosure relates to orthopaedic implants and, in particular, to acetabular cup assemblies of hip prostheses.
2. Description of the Related Art
Total hip arthroplasty is often used to restore function to a diseased or injured hip joint. Positions and directions relative to the hip joint may be described in terms of proximal being nearer the hip joint, distal being further from the hip joint, anterior being nearer the front of the body, posterior being nearer the back of the body, medial being nearer the centerline of the body, and lateral being further from the center line of the body. In total hip arthroplasty, surfaces of the femur and pelvis are prepared, such as by cutting and/or reaming, and replaced with substitute implants. In a typical case, the implants include a hip stem component, a femoral head component, and an acetabular component.
The acetabular component typically includes a shell having substantially hemispherical outer and inner surfaces. The outer surface is configured for bone ingrowth to anchor the shell in the acetabulum, and the inner surface receives a prosthetic liner formed of a bearing material such as ultra high molecular weight polyethylene (UHWMPE), for example. During the total hip arthroplasty procedure it is often desired to use provisional liners on a trial basis to ascertain the kinematics and/or range of motion of the joint prior to final fitting of the prosthetic liner into the shell. In this procedure, a provisional liner is temporarily secured within the shell, such as via one or more fasteners, and permits a trial reduction of the joint in which the femoral head is received within the provisional liner to assess the kinematics and/or range of motion of the joint. The provisional liner may be removed and replaced with other provisional liners as necessary until the proper size and/or orientation is determined. The provisional liner is then removed and replaced with a prosthetic liner corresponding to the selected provisional liner.